Change icons for batch select in the panel grid (the white circles) more visible

[HannahSonntag]

Currently the white circles are invisible on white background.
Rather use a gray-transparent circle turning opaque when active. (Similar to google photo)

[eidens]

The panel select button should now be much more visible on white images as it's now filled with a light and slightly transparent grey that is different from the border color. Even on images with the same color as one of background or border, the other one is still visible.

[HannahSonntag]

I like the visibility, it's much better now.
But I find the select button looks goofily big now. Can we reduce the size? Something like 50% almost?

[eidens]

The buttons are now around half as wide as before.

[HannahSonntag]

While these are much better visible now, we would like them to be more like the ‘google photo’ thing. But since not alle SmartFigures on a users Dashboard are selectable to the user, it is has to become clear to the user, why certain SmartFigures cannot be selected.
Therefore: When hovering over the SmartFigure there should be a ‘shadow’ covering the top bit of the Smartfigure (as in google photo) and the ‘select’ button is then clearly visible- regardless of the image color. But for panels that one cannot select, there will be no select icon. But instead a ‘conditional tool tip’ informing the user ‘you are not the owner’.

[HannahSonntag]

Edit: the icons in the lower right corner (sharing status) are also rather difficult to see and in the user testing everyone overlooked them.
So the 'shadow' when hovering over the image could also extend over these icons to make them more visible -regardless of the image background color.